There are a range of ballistic trajectories that can work. If you want to get there faster, you can use a shallower trajectory (they usually call this a depres

There are a range of ballistic trajectories that can work. If you want to get there faster, you can use a shallower trajectory (they usually call this a depressed trajectory). This takes more energy, so you get a shorter range for a given missile. The other problem is that the warhead spends more time in the atmosphere. Most ballistic missiles use unguided reentry vehicles, so the best accuracy comes from a high trajectory that comes almost straight down onto the target, so it spends the least time interacting with the unpredictable atmosphere. However, if the reentry vehicle is guided, depressed trajectories become more practical. The U.S. did this in the past with the Pershing II, which had terminal radar guidance, and we have a half-way version of this with path length fusing on the Trident II, where the warhead is not guided, but the detonation point is controlled based on trajectory error. Russia has tested these in the past few years and could have deployed them. IMO it's an underappreciated threat because it could allow attacks against hard targets with less than 10 minutes of warning.